1. Field of the Invention
The invention relates to a data recovery device and method. Particularly, the invention relates to a data recovery device and method of an optical storage system.
2. Description of Related Art
In an optical storage system, a radio frequency (RF) signal picked up from a disc surface by an optical pickup head has to be processed by a data recovery device in order to recover a modulation signal representing real data and a clock signal. Regarding the signal pickup, the RF signal is usually deformed due to interferences, so that the data recovery device cannot recover the modulation signal representing the real data, for example, a tilt error.
There are two types of the tilt errors, which include a radial tilt error shown in FIG. 1A and a tangential tilt error shown in FIG. 1B, where a label 110 indicates a disc, and a label 120 indicates a track of the disc. As shown in FIG. 1A, the radial tilt error is an angle α formed between a light and a normal line 130 of a radial direction, which is mainly caused by a shape variation of the disc. Moreover, as shown in FIG. 1B, the tangential tilt error is an angle β formed between the light and a normal line 140 of a tangential direction, which is generally caused by poor assembling of the device.
In order to resolve the problem of the tilt error, U.S. Pat. No. 6,282,161 discloses a tilt adjusting method and apparatus using jitter feedback, in which a displacement sensor is used to observe an angle of a light reflected by the disc, so as to obtain a tilt direction. Then, a tilt driving motor is used to correspondingly adjust an objective lens to improve quality of an optical path. However, according to such method, the displacement sensor and the tilt driving motor have to be additionally configured, which may lead to a high cost of the optical pickup head. In other words, such method cannot be applied to a low cost digital video disc (DVD) player, and an application range of the optical pickup head is limited.